This drive to war is one of the mysteries of our time

Weightier decisions than those due to be taken in the next two to three weeks can hardly be imagined. In rapid sequence, UN inspectors will make their report, Bush will give his state of the union address, the security council will meet to discuss Iraq, and the Israelis will go to the polls. Tony Blair, the president's principal supporter, will meet both Bush and Jacques Chirac, who is emerging as the leader of European opposition to a war against Iraq, in summits only a few days apart.

These decisions are particularly perplexing, for all but the committed core in the Bush administration, because the drive to make war on Iraq - or, rather, the larger American policy of which that drive is a part - is one of the most mysterious projects of modern times. How and why the administration conceived and nurtured it is still unclear. It is possible to say, however, that an influential group, which grew in numbers over time and quickly came to include the president, intuited rather than reasoned that Saddam Hussein and his regime represented both a danger that had to be met and an opportunity that had to be seized.

They have nevertheless marshalled a case for war that is substantial, a case that fair-minded people might be inclined to accept more widely than they do - were it not that the case against war is at least equally strong. But it is the utter confidence of the American war party in the rightness of its cause, the sense that, with it, the war and the grand strategy of which it is a part are articles of faith, that is the best argument of its opponents. How can there be such an unblinking conviction that its course is right in as uncertain and as complex, and as new a world as the one we are living in today?

Whatever is thought of this American purpose, there is no denying its energy and force. The nations, including the people of the United States, are not deciding in the coming weeks whether or not there will be war with Iraq. As Bush said recently: "I get to decide that." But they are choosing whether America and Britain will wage a lonely combat, and whether the attempt to relate the American purpose to the purposes of others, to channel it through international institutions, and to make it both more legitimate and more controllable, will be abandoned or continue.

But here it is necessary to be as hard on many of the opponents of war as on its proposers, as well as to clear away the misleading idea that evidence that Saddam is concealing weapons of mass destruction is at the centre of the argument. It is at the centre of the manoeuvring, yes, but not of the argument. Among those knowledgeable about Iraq there are few, if any, who believe he is not hiding such weapons. It is a given. We print accounts of them, with diagrams and charts, in our newspapers every day. That is why both the Americans and the British insist that it is not just a matter of the inspectors being able to go where they please, but of Iraq handing over the weapons that everybody knows they have.

In these circumstances, to treat Iraq as if it were an Agatha Christie thriller which it is necessary to read to the end is ludicrous. Of course, to wait for the moment of discovery may well be the right course procedurally, because it means the appropriate UN resolutions can be invoked. It may also be the right course psychologically, because it affects public support. But acting as if it is still genuinely an open question whether Saddam is cheating is dishonest, and likely to be a cover for opposition to the war on other grounds - whether those grounds are good or bad.

It is also dishonest to argue that, with the inspectors ranging over the country without serious obstacle to their activities and with the Iraqi regime clearly in chastened mood, Iraq is now once again effectively contained, so there is no need for military force. Containment has been revived, and the international community has been galvanised into a new attitude toward Iraq. But both of these are consequent on the American will to war and the increasingly visible preparations for it. Does anyone imagine that if those American troops were stood down, Iraqi co-operation would continue for long?

Yet it is here that there is a chance for a bargain between the United States and its allies that could take us through the summer and beyond. That bargain would be that America would shoulder the costs and risks of a prolonged deployment in the Gulf if the allies engaged to continue to take containment seriously, and to draw a line at some agreed point in the future where military action would once again be on the table, this time without any ifs or buts.

The advantages? Time, for Saddam to convict himself, and for the inevitability of his end to work its way more deeply even into his inner circles. The disadvantages for those driving American policy? Loss of momentum, loss of prestige, and gambling on friends they do not fully trust. The chances therefore are not high, particularly as, in the American and British view, similar bargains have been made in the past and not honoured.

In Washington, there is an obvious feeling that this is a tide that must be taken at the flood. If war therefore comes soon, and America and Britain fight it alone and without international endorsement, the precedent will not be a good one, and the damage to transatlantic relations will be large, as will that to relations between Britain and its European partners.

Even if the war is a low-casualty success, and the liberation of the Iraqi population can be counted as a boon, the dangers arising from a consequent American attempt to put into practice a master plan for the region are clear. Yet it has to be said that there is a need for a new approach by America and Europe to the Middle East. But that needs to be something more modest in its aspirations and more sympathetic to Arab sensibilities and claims than that which the wilder spirits in Washington seem to be contemplating.

Perhaps the hawks can be bid down. A victory, with all the immediate difficulties and intricacies it would bring, could well sweep some unrealistic ambitions aside, as well as forcing the US to face problems in the region which it has been, until now, postponing. Victory, far from confirming the neo-conservatives in a position of dominance, might open up alter- natives and give other elements in the American establishment, including the uniformed military, whose doubts have been evident in recent months, a bigger voice in debate. The UN and America's allies would have important levers of influence in the aftermath of a war, for the US would likely be in need of their money, their troops, and the legitimacy they could bring. Politics - fortunately - never stops.